Until the early 1940s geochemistry was primarily concerned with defining elemental abundances in minerals and rocks. Since that time, investigators have broadened the scope of their research significantly, studying, for example, the continual recycling of the Earth’s constituent materials through agencies of the hydrosphere and atmosphere coupled with seafloor spreading, mountain building, and other processes involving the terrestrial crust. Modern geochemical research also includes the study of chemical transformations of biological materials in rocks and the cyclic flow of individual elements (and their compounds) between living and nonliving systems. Since the 1960s, certain areas of geochemical research have become interlinked with cosmology—e.g., the study of the origin and relative abundance of elements in the solar system, the Milky Way Galaxy, and the universe as a whole; the chemical composition of meteorites; and the ages of terrestrial and lunar rocks.

Learn More in these related articles:

The early studies of the radioactive decay of uranium and thorium into lead caused the British physicist Ernest Rutherford to suggest that this process could be used to determine the age of rocks and consequently of the Earth by observing the amount of helium retained by a rock relative to its uranium and thorium contents. Mass spectrometers capable of measuring isotopic ratios allow the...

Since the early 1970s researchers have developed extremely sensitive methods of chemical analysis, providing the ability to detect minute amounts of materials. Many chemical elements are transported in very small quantities by fluids flowing in the Earth, so that a systematic measurement of such trace elements may help in locating their sources. Trace elements are sometimes associated with...